Hello- I've read so many threads on various ext HD's to use with Time Machine & to think I can't name one good recommendation & that's what all the questions are in the threads. So, my conclusion is to go the expensive route and stick with Apple & Time Capsule. At least it's suppose to work together and if there are problems I can deal with it through the warranty & support. Plus, I'll easily figure(read) how to wire it up & I know it's all compatible. So, my question is 1TB or 2TB model? I have started shooting all my images in RAW files which will be the standard from now on, & have about 2000 already. I also have aprox. 2000 ~3MB jpg's now and a few short 15sec videos. I have about 7 CD's full of jpgs and ~500 slides I want to scan/digitize and download to the system. I will be drastically increasing the RAW photo's. I build web sites & have hundreds of thumbnails & smaller web based images associated with those sites which I keep. What happens when the backup HD gets filled, I assume you get some pop up telling you that. Do you just unplug the HD and save it?, then buy a new one & plug that in? ( but then you want to start from where the previous HD left off without copying everything on the first)? With 2TB maybe I would never have to worry about this?